Screening basket for oscillating centrifuge



SCREENING BASKET FOR OSCILLATING CENTRIFUGE Filed Aug. 2, 1957 Oct. 6, 1959 w a. J. HECKMANN ETAL 2 Sheets-Sheet 1 WM P7 C m. 9 d flu. ,5. a 3. @76 w r r Y B SCREENING BASKET FOR OSCILLATING CENTRIFUGE Filed Aug. 2, 1957 Oct. 6, 1959 w. G. J. HECKMANN ETAL 2 SheetsSheet 2 A F/G.2

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III!!! IIIIII IIIIIH 7/4 SCREENING BASKET FOR OSCILLATING CENTRIFUGE Wolfgang Gertrud Joseph Heckmann, Koln-Deutz, Joseph N. Hubert Becker, Koln-Mulheim, and Fritz Steven,

Rodenkirchen, Germany, assignors to Kliickner-Humboldt-Deutz Aktiengesellschaft, Koln-Deutz, Germany This invention relates to a centrifuge, commonly known as an oscillating centrifuge for separating water from fine granular material with a rotating conically shaped screening basket which is simultaneously axially oscillated to discharge the separated particles.

By the present invention there is provided an improved screening basket for a centrifuge of the above type, which screening basket comprises a substantially upright screening surface formed of a plurality of wires or rods of which the upper ends of the'wires or rods are equally spaced from one another on a common circle and their lower ends are arranged in spaced and alternatively staggered relationship on two difierent circles such that the lateral spacing between each of the wires or rods is uniform along the lengths thereof. A basket ofthis type is simply constructed and is extremely durable.

In the drawings:

Fig. 1 is a schematic vertical cross sectional view of an oscillating centrifuge.

Fig. 2 is an enlarged vertical cross sectional view of a screening basket formed with rods of circular cross section.

Fig. 3 is a partial bottom view of the basket shown in Fig. 2.

Fig. 4 is a partial view of the top edge of the screening basket as viewed from A.

Fig. 5 is a view taken along the line VV of Fig. 2.

Fig. 6 is a partial view taken similarly to Fig. 5 in which the screening basket is formed of rods having a trapezoidal cross section.

The centrifuge comprises an open top frustro-conically shaped screening basket 1, of which the generatrix of the screening surface is inclined at approximately 5 to 15 to the vertical. The outer casing of the screening basket is formed of rods 2 and 3 which may, as shown in Figs. 2 and 4, be of circular cross section having a diameter of approximately 3 to 8 mm. and may be of a weldable, non corrosive and durable material such as chrome nickle steel. As shown inIFig. 4, the upper ends of the rods 2 and 3 are arranged on a common circle 4 and spaced from each other at a distance a, as for example approximately 3 mm. Joining the rods 2 and 3 there is a wound about each a wire 5 having a diameter equal to the spacing a. In this manner the rods 2 and 3 are maintained equally spaced from eachother on the circle 4.

At their lower ends the rods 2 and 3 are arranged in staggered relationship on two circles'8 and 9 such that the rods 2 lie on the outer circle 8 and the rods 3 on the inner circle 9. As shown in Fig. 5 the rods 2 and 3 are spaced from each other at a distance a of approximately 3 mm. To maintain this spacing the rods are joined by a high tensile strength Wire 10.

Since the upper and the lower ends are each spaced at an equal distance a of 3 mm., there is provided between each of the rods a vertical slot 11 which is equal laterally spaced along its entire length. Encircling the rods 2 and 3 are bands 14 which are secured thereto as by welding. These members also assist in maintaining the desired spacnited States Patent 0 2,907,465 Patented Oct. 6, 1959 ing of the slot 11. Welding joints which serve to connect the rods to each other may be substituted for the bands 14.

The rods 2 and 3 on the upper ends have welded thereto a lateral flange 6 and at their lower ends an annular base plate 12. The rods 3 are longer than the rods 2 such that the former are seated and then welded within a circular recess 13 provided'in the base plate 12 thereby to center the screening surface 2 thereon. On the outer edge of the base plate 12 there is fastened as by welding a band 15 from the upper edge of which laterally projects an annular flange 16. The upper edge of the band 12 is also welded to the rods 2 thereby to increase the rigidity of the screening basket 1.

Inside the screening basket 1 and fastened on the base plate 12 is a truncated cone shaped hood 17 with. a cone 18 on top of it. Carried on the hood 17 by means of a plurality of ribs 19 is a conical shell 20 which is provided with an inlet opening 45 for the slurry to be separated. In the hood 17 there is disposed a hollow stationary center post 21 Which is supported on the machine frame 22. Rotatably journaled on the center post 21 is a hollow drum shaft 23 which is provided at its upper and lower ends respectively with collars 24 and 25. Engaging the edge of each collar there are three or more sets of springs 26, 27 which are disposed between the base plate 12 and the collars 24 and 25 thereby to support the screening basket for oscillating movement. On the lower collar 25 there is secured a pulley 28 on which is entrained the driving belt 29 which is connected to a motor not shown. The torque which is transmitted to the drum shaft by the motor is transmitted through the springs 26, 27 to the screening basket 1 such that it rotates with the shaft 21.

In the hollow center post 21 there is located a cam shaft 30 which is operated by a motor not shown. Embracing the cam shaft 30 is a pitman 31 which extends through the hollow center post 21 and is coupled at its upper end with a roller bearing 32 and a loose coupling 33 connected to the hood 17. In this manner the hood 17 is oscillated at a frequency of 30 vibrations per minute with a magnitude of 2 mm.

The screening basket is encircled by a stationary tank 34, the base of which is provided with an outlet pipe 35 for discharging the separated water. The tank is fastened to the outer frame wall 37 by means of ribs 36 which wall 37 is supported on the machine base by means of ribs. The tank 34 encircles the screening basket 1 such as to provide an annular compartment 38. Secured to the lower edge of the frame wall 37 are lugs 39 which rest on vibration isolating bumpers 40 supported on the bunker 41.

The slurry from which the water is to be separated is inserted into the centrifuge through the inlet 45 into the annular compartment 42. During the passage therethrough the slurry is accelerated in the direction of rotation of revolving elements 17 and 20. After its passage through the annular compartment 42 the slurry is cast on the screening surface of the rotating and oscillating screening basket 1 whereat it travels upwardly and water is separated therefrom and discharged through the spaces 11. Whereupon the water is entrapped in the tank 34 and discharged through the outlet 35. The dried particles are discharged over the flange 6 on top of the basket 1 and fall through the compartment 38 into the bunker 41.

In place of the circular rods as above described, there may be substituted rods of different cross section, as for example quadrangular or the like. Thus, for example as shown in Fig. 6 a rod 43 of trapezoidal cross section may be used. As shown, the rods 43 are arranged such that the wider sides are facing inwardly. The rods 43 6 are arranged relatively't'o each other to provide a spacing-44 which'is uniformly maintained throughout the height of the basket 1. Since the sides of the rods 43 taper the clearance of particles which may become wedged in 'the slots M is greatly facilitated. Under some circumstances itmay be desirable to arrange the rods such that they form vertically tapering slots.

*What we "claim is:

l screening basket for a centrifuge having an inverted substantially frustro-conical screening surface, said surface comprising a plurality of substantially vertically disposed elongated members of uniform cross-section of which the upper ends are arranged on a common circle and'equally spaced from each other, and the lower ends of said elongate member are arranged in alternating staggered-relationship on two different circles, said lower ends being spaced from each other a distance equal to said equal distance between said upper ends, whereby there is formed a substantially vertical slot ofuniform width between each of said elongate members.

2. The invention as defined in claim 1 in which-said elongate members are wire.

3. The invention as defined in claim 1 in which said elongate members are rods.

4 The invention as defined in claim 1, wherein the two circles on which the lower end of said elongated-members are arranged are in the same plane.

5. 'The invention as defined in claim 4, wherein said two circles are concentric.

6. The invention as claimed in claim 1, wherein said elongated members have an isosceles trapezoidal crosssection.

7. The invention as claimed in claim 6, wherein the Wider sides of said isosceles trapezoidal cross-sectioned members face the interior of the basket.

8. The invention as claimed in claim 1, wherein said screening basket comprises anannular base plate having a circular recess and a circular upright band secured to said base plate, the lower ends of said elongated members which are arranged on one of said circles projecting into said recess and being welded to said base plate and the lower' en'ds of said elongated members which are arranged in the other one of said circles being Welded to said band. 7

9. The invention as claimed in claim 1, wherein the upper ends of said elongated members are supported by and welded to a lateral outer flange.

10. A screening basket for a centrifuge having an inverted substantially frustro-conical screening surface, said surface comprising a plurality of substantially vertically disposed, slightly inclined elongate members of uniform cross-section of which the upper ends are arranged on a common circle and equally spaced from each other, a base plate, the lower ends of said elongate members being seated on said base plate and being arranged in alternating staggered relationship on two different but concentric circles, said lower ends being spaced from each other a distance equal to said upper equai distance between said ends, whereby there is formed a substantially vertically disposed, slightly inclined slot of uniform width between each of said elongate members.

References Cited in the file of this patent UNITED STATES PATENTS 748,756 Kuchenmeister Ian. 5,1904 2,516,963 Derbenwick et a1. Aug. 1, 1950 2,766,602 'MacGregor Oct. 16, 1956 2,781,130 Heckmann et al. Feb. 12, 1957 2,806,603 Van der Molen Sept. 17, 1957 

